Packaging machine for forming and filling bags of different lengths and widths

ABSTRACT

Bags which may vary in length and width within preselected ranges from one run to another are formed from a web of flexible material and are filled with a quantity of product as they are advanced in vertical planes along a horizontal path by a packaging machine. To reduce the number of adjustments necessary for changing over the machine from running bags of one length and width to running bags of a different length and width, the machine is capable of being set up to maintain the upper ends of both long and short bags moving along a common operating or datum line during the advance of the bags and, at the same time, to maintain the longitudinal center lines of both wide and narrow bags in exact coincidence with the working centers of various mechanisms spaced along the path for operating on the bags before, during and after filling. The disclosure also specifically pertains to a number of new and improved mechanisms for forming and handling the bags and to the drive mechanism of the machine.

United States Patent Johnson et al.

PACKAGINGMACHINE FOR FORMING AND FILLING BAGS OF n DIFFERENTLENGTHS AND WIDTHS [72] Inventors: Kenneth Johnson; Robert F. Lense,

' both of Rockford, Ill.

[7 31 Assignee: Rexham Corporation, New York,

31. 22 Filed: Sept. 30, 1970 [21] Appl. No.: 76,946

Related US. Application Data [60] Division of Ser. No. 706,817, Feb. 20, 1968,

Pat. No. 3,553,934, which is a continuation-inpart of Ser. No. 689,177, Dec. 8, 1967, Pat. No. 3,545,166.

[52] US. Cl ..53/183, 198/178 [51] Int. Cl. ..B65b 9/08 [58] Field of Search ..53/28, 29, 180, 183, 303; 198/179,137, 210

[56] References Cited UNITED STATES PATENTS 3,462,913 8/1969 Bodolay et al ..53/183 I 2,877,609 3/1959 Bodolay et al. ..53/ 182 X 2,649,671 8/1953 Bartelt ..53/ 183 X 2,330,361 9/1943 Howard ..53/28 2,654,195 10/1953 lrmscher ..53/29 3,545,166 12/1970 Johnson et al. ..53/183 X 3,230,687 1/ 1966 Nutting et al ..53/28 X Oct. 24, 1972 2,676,442 4/ 1954 Gaubert ..53/183 2,649,673 8/ 1953 Bartelt ..53/183 2,649,674 8/ 195 3 Bartelt ..53/183 Primary Examiner-Theron E. Condon Assistant Examiner-Eugene F. Desmond AttarneyWolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[57] ABSTRACT Bags which may vary in length and width within preselected ranges from one run to another are formed from a web of flexible material and are filled with a quantity of product as they are advanced in vertical planes along a horizontal path by a packaging machine. To reduce the number of adjustments necessary for changing over the machine from running bags of one length and width to running bags of a different length and width, the machine is capable of being set up to maintain the upper ends of both long and short bags moving along a common operating or datum line during the advance of the bags and, at the same time, to maintain the longitudinal center lines of both wide and narrow bags in exact coincidence with the working centers of various mechanisms spaced along the path for operating on the bags before, during and after filling.

The disclosure also specifically pertains to a number of new and improved mechanisms for forming and handling the bags and to the drive mechanism of the machine.

7 Claims, 21 Drawing Figures CROSS-REFERENCE TO RELATED APPLICATIONS This application is ,adivision of our copending application Ser. No. 706,817, filedFe b. 20, 1968, now U.S. Pat. No. 3,553,934 which, in turn, is a continuation-inpart of our application Ser. No. 689,177, filed Dec. 8, 1967, now U.S. Pat. No. 3,545,166.

BACKGROUND OF THE INVENTION This invention relates to a packaging machine wherein bags are formed from a continuous web of flexible material in a bag-making section of the machine and thereafter are transferred to a bag-filling section for filling with measured quantities of product.

In the bag-making section of such a machine, the web is folded into a pair of face-to-face strips which are advanced in upright planes along a substantially horizontal path into a sealing station where they are sealed together along longitudinally spaced lines extending crosswise of the strips so as to form a row of I bags interconnected at their adjacent side edges by the newly formed seals. Thereafter, the leading bag is severed from the row and is transferred to the bagfilling section of the machine.

In the bag-filling section, the bags are advanced open end up along an extension of the path by a conveyor which includes a series of spaced clamps operable to receive and grip the bags as the latter are cut from the row and operable to hold the bags for advancement in generally upright planes. During such advance, various operating mechanisms spaced along the conveyor perform functions such as preparing the bags for filling, depositing the product into the bags, and sealing the open ends of the bags to enclose the product therein. The machine is particularly characterized by its ability to be easily changed over from an operation of forming and filling bags of one size to an operation of forming and filling bags of a different size within a preselected range of sizes.

SUMMARY OF THE INVENTION One aim of the present invention is to provide new and improved adjustable mountings for a sealing unit adapted to seal the strips together and for a cutter adapted to sever the bags from the strips, the mountings facilitating adjustment of the sealing unit and the cutter along the bag path when the machine is changed over to run bags of a different width. A further object is to provide an adjustable sealing unit in which the sealing force applied by the unit is centered on the vertical centers of the seals of the bags regardless of the length of the seals.

In other aspects, the invention is characterized by the "novel construction and location of the conveyor of the (bag-filling section to prevent the conveyor from being fouled by the product being packaged and to prevent the conveyor from interfering with the bag operating mechanisms; by a unique peaked roof which sheds loose product away from the machine; by the construction of the bag-holding clamps in the form of inexpensive cartridges well adapted for manufacture by modern mass production techniques; and by the provision of relatively simple and trouble-free mechanisms for opening and closing the clamps during transfer of the bags to and from the bag-filling section of the machine.

Other objects and advantages will become apparent as the following description proceeds, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical bag which may be formed and filled by a packaging machine embodying the novel features of the present invention.

. FIG. 2 is a schematic view of the bag-making section of the machine.

FIG. 3 is a schematic view illustrating the manner of maintaining the upper ends of bags of various lengths extending along a common datum line.

FIG. 4 is a schematic view illustrating the manner of maintaining the center lines of bags of various widths in coincidence with the working centers of the operating mechanisms of the machine. I

FIG. 5 is a fragmentary side elevation of the bagmaking section when viewed from the front side of the machine.

FIG. 6 is an enlarged fragmentary view of the forward end portion of the bag-making section shown in FIG. 5, parts being broken away and shown in section.

FIG. 7 is an enlarged fragmentary cross-section taken along the line 7-7 of FIG. 6.

FIG. 8 is a fragmentary cross-section taken along the line 8-8 of FIG. 6.

FIG. 9 is an enlarged fragmentary cross-section taken along the line 9-9 of FIG. 5.

FIG. 9a is a fragmentary perspective view of parts shown in FIG. 9.

FIG. 10 is an enlarged fragmentary cross-section taken along the line l0--l0 of FIG. 5.

FIG. 11 is a fragmentary cross-section taken along the line 11-11 of FIG. 10.

FIG. 12 is a fragmentary cross-section taken along the line 12-12 of FIG. 11.

FIG. 13 is an enlarged elevation of parts shown in FIG. 12.

FIG. 14 is an enlarged elevation of parts shown in FIG. 12 with certain elements being broken away and shown in section.

FIG. 15 is an enlarged fragmentary cross-section taken along the line 15-15 of FIG. 12.

FIG. 16 is a fragmentary side elevation of the bagfilling section as viewed from the front side of the machine.

FIG. 17 is an enlarged fragmentary cross-section taken along the line 17-47 of FIG. 16.

FIG. 18 is an enlarged fragmentary cross-section taken along the line 18-18 of FIG. 16.

FIG. 19 is an enlarged perspective view of parts shown in FIG. 18.

FIG. 20 is an enlarged fragmentary cross-section taken along the line 20-20 of FIG. 18.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings for purposes of illustration, the invention is embodied in a packaging machine for converting a continuous strip or web 30 of flexible material such as foil, plastic or paper into pouches or bags 32, filling the same with one or more measured quantities of product, and thereafter closing the filled bags and transferring the bags to a suitable receptacle or to an automatic cartoner (not shown). Herein, each bag is formed of heat-scalable material such as polyethylene film and comprises two opposing face-toface side panels 33 joined along their lower margins by a fold 34 and sealed together along their two side margins as indicated at 35. The product, which in this instance consists of a granular or powdered food substance, is deposited into the upper end of the bag and is enclosed therein by a heat seal 36 joining the upper margins of the side panels.

Basically, the machine comprises a bag-making section 37 (FIGS. 2 and with which the bags 32 are formed as the web 30 is advanced in a horizontal direction along a predetermined path. Downstream from and disposed end-to-end with the bag-making section is a bag-filling section 39 (FIGS. 2 and 16) to which the newly formed bags are transferred for filling and closing during advancement along an extension of the path.

In forming the bags 32, a length of the web 30 is drawn endwise off of a supply roll 40 which is joumaled to turn about a horizontal axis on a support 41 (FIG. 6) projecting forwardly from the front end of the bagmaking section 37. From the supply roll, the web is trained upwardly over a guide roller 43 and downwardly around a spring-loaded dancer roller 44 operable to maintain tension on the web and mounted for up and down movement in a pair of slotted guides 45 upstanding from the support. The web then passes upwardly over a second guide roller 46 and downwardly beneath a forming member or folding plow 47 which folds the web upwardly along its longitudinal center line to form a pair of face-to-face strips 49 disposed in vertical planes and each being equal in height to approximately half the width of the web. As the strips are advanced along the path, a pair of heated side sealing bars 50 (FIGS. 2 and 9) disposed in upright positions on opposite sides of the strips periodically reciprocate into and out of engagement with the same to seal the strips together along longitudinally spaced lines 51 (FIGS. 4 and 5) extending crosswise of the strips thereby to form a row of connected bags having open upper ends. During such sealing and just prior to the time the bags are filled, their upper edges straddle and are spread apart by elongated splitter bars 53 and 54 (FIGS. 2, 5 and 16) extending above the path along the bag-making and bag-filling sections 37 and 39, respectively.

With continued advance of the folded web 30 after sealing, a cutting unit 55 (FIGS. 2 and 12) disposed downstream from the sealing bars 50 separates successive bags 32 from the leading end of the row by cutting through the seals 51 midway between their side edges so that each seal 51 forms the trailing side seal 35 of one bag and the leading side seal 35 of the next succeeding bag. The sealing bars and the cutter are timed to operate once each time the web advances through a distance equal to the width of the ultimate bags to insure sealing and servering of the web along properly spaced lines.

Upon being severed from the web 30, each bag 32 is delivered to the bag-filling section 39 of the machine at a transfer station 56. In this instance, the bag-filling section includes a conveyor 57 (FIGS. 2 and 11) for picking up each cut off bag and for advancing the bags in spaced edgewise relation and in upright positions through a number of stations where various mechanisms operate on the bags. For example, during advance of the bags by the conveyor, a bag opener 59 (FIGS. 2 and 16) positioned alongside the conveyor in a filling station 60 first pulls apart the upper ends of the side panels 33 of each bag and thereafter a conventional dispenser 61 (FIGS. 2 and 16) disposed above the conveyor deposits a measured charge of product into the opened bag through a spout which is usually lowered into the bag. The filled bags then are advanced between a pair of horizontal sealing bars 63 (FIGS. 2 and 16) extending longitudinally of the bag path and periodically shiftable into'engagement with the bags to seal the upper ends closed and thereby form the top seals 36. After advancement between a pair of similarly disposed cooling bars 64 which harden the newly formed top seals, the bags are removed from the conveyor and are transferred to the cartoner by a pick-off device 65 (FIGS. 2 and 16) located downstream from the cooling bars.

In many packaging operations, a single machine of the above type often may be used for forming and filling a series of bags of one width and then switched over to form and fill a series of bags of a different width. This is particularly true not only with respect to smaller plants in which different products may be packaged with the same machine on different days but also from the standpoint of contract packagers who may run one width of bag for a few hours, switch over to another width for a few hours, and then make still another changeover in the same day.

The machine is based on a concept that all bags, regardless of their width can be kept centered on the working centers of various ones of the operating mechanisms of the bag-filling section 39 during advancement of the bags and that, by such centering of the bags, the machine can be changed over from running a first series of bags of one width to running a second series of bags of a different width without requiring adjustment of the working centers of the mechanisms along the path and into coincidence with the longitudinal center lines of the second bags during the interval between the two runs. In carrying out this concept, an imaginary datum line is established upon which each bag formed during a run is centered as the bag is cut off from the web 30. Certain operating mechanisms of the bag-filling section 39 (such as the bag-opener 59, the dispenser 61 and the pick-off device 65) are set up with their working centers operating permanently along lines which are spaced from the datum line by distances such that, with each bag centered on the datum line during cut off, the centers of the bags automatically coincide with the working centers when the bags are subsequently presented to the mechanisms. When changing over the machine to form and fill a second series of bags which differ in width from those of the previous run, relatively simple adjustments are made to the cutter 55 and the conveyor 57 to maintain the second bags centered during cut off on the same imaginary datum line as the firstbags so that the second bags, when presented to the operating mechanisms, also will coincide with the working centers of the mechanisms with-the latter remaining set up exactly the same as during the preceeding run.

While the above concept is applicable equally well to a packaging machine adapted to advance the web 30 and the bags 32 with a continuous and uninterrupted motion, it herein is disclosed specificallyin conjunction with a so-called intermittent motion machine of the type in which the web and the bags are advanced stepby-step with the several operating mechanisms working on the web and the bags during dwells which occur in the motion between successive steps. More specifically, step-by-step advance of the web is effected by a pair of coacting feed rolls 66 and 67 (FIGS. 2 and frictionally engageable with the web between the sealing bars 50 and the cutter 55 and intermittently rotatable through arcs sufficient to advance the web through steps equal in length to the width of the bags being formed. For example, when forming bags 32 having a width of four inches, the feed rolls will be set to advance a four inch length of web during each step. The side sealing bars move into engagement with the folded web during each dwell and'thus the distance between successive side seals 51 corresponds to the width of the bags. The cutter also operates while the web is dwelling and is spaced downstream from the side sealing bars a distance equal to a multiple of the bag width so that, after each advance of the web, one side seal 51 dwells alongside the cutterwith the bag on the leading end of the web projecting downstream of the cutter and positioned in the transfer station 56, By way of example and as shown schematically in FIG. 4, the spacing SC between the sealing bars and the cutter may be established at 12 inches when the machine is set up to run bags 32 each having a width of 4 inches.

Before each leading bag 32 is cut off from the web 30, its leading edge is gripped in the transfer station 56 by a pair of grippers or clamps 69 (FIGS. 4, 17 and 19) on the conveyor 57. Herein, the conveyor comprises an endless chain 70 having a straight run passing through the transfer station and alined with the path of the web. Several pairs of the clamps 69 are attached along the chain and are equally spaced from each other a distance greater than the width of the widest bag to be handled by the machine, the spacing or pitch P (FIG. 4) of the clamps being approximately eight inches in this instance. The chain is advanced intermittently and is timed such that one pair of clamps is always dwelling in the transfer station each time the leading end of the web is advanced past the cutter 55. During eachsuch dwell, the clamps in the transfer station are opened to receive the advancing end of the web and, shortly after the latter dwells, the clamps are closed thereby to grip the leading bag securely before the cutter severs the bag from the web.

During cut off, each bag 32 dwells in the transfer station 56 with its longitudinal or vertical center line, lying along an imaginary vertical line DL (FIGS; 2,-and 4) which is disposed parallel to the cutter 55 in the plane of the bag. The line DL defines the datum line to which the positions of the working centers of certain mechanisms of the bag-filling section 39 are referenced. To center the bags on the datum line during cut off, the horizontal spacing CD (FIG. 4) between the cutter and the datum line is always set at half the width of each bag and, in the case of the 4 inch bags 32, the spacing CD is 2 inches. Also, the chain 70 is positioned such that, with a pair of clamps 69 dwelling and properly gripping the leading edge of a bag in the transfer station, the horizontal spacing DG between the datum line DL and a vertical line of reference on the clamps is a predetermined value. For purposes of discussion, it may be assumed that the line of reference on the clamps is taken along the leading edge of a bag in the transfer station. Thus, the distance D6 is two inches when the four inch bags 32 are being run.

After each bag 32 has been gripped by a pair of clamps 69 and cut off from the web 30, it is advanced by the chain 70 and dwells successively in the different stations where the bag opener 59, the dispenser 61, the

top sealing and cooling bars 63 and 64, and the pick off device 65 are located to operate on the bag during the intervals when the latter is dwelling. As shown schematically in FIG. 4, these various mechanisms are located along the path of the chain with their operating or working centers advantageously lying along or centered on imaginary vertical lines which are spaced horizontally from the datum line DL by multiples of the pitch P of the clamps. In addition, the chain is timed to advance each gripped bag in equal steps each corresponding in length to the pitch of the clamps. Accordingly, since the bag initially dwells during cutoff in a centered position on the datum line DL and since the operating mechanisms are spaced from the datum line by multiples of the bag advance, the bag subsequently dwells in each of the stations with its vertical center line coinciding exactly with the working centers of the mechanisms. In this way, the bags are alined perfectly with the mechanisms as the latter operate on the bags.

Bags which are wider or narrower than the bags formed on a preceding run are kept centered on the same datum line DL during cutoff by adjusting the center line of the cutter 55 relative to the datum line between runs by a distance equal to one-half the difference between the width of the previously formed bags and the width of the bags to be formed on the next succeeding run. Also, to effect transfer of the wider or narrower bags to the conveyor 57, the position which the clamps 69v assume when dwelling in the transfer station 56 is adjusted relative to the datum line by an amount equal to the adjustment of the cutter but in an opposite direction.

To explain these and other adjustments which are made when the machine is changed over from running bags of one width to running bags of a different width, let it be assumed that the machine has been set up as described above to run 4 inch bags 32 and that it is desired to adjust the machine to run narrower bags 32N (FIG. 4) each having a width of 3 inches. First, the feed rolls 66 and 67 are adjusted to'advance the web 30 through 3 inch steps instead of the 4 inch steps of the former run. Next, the cutter 55 is adjusted from its previous position and toward the datum line DL by a distance equal to one-half the difference between the width of the bags 32 and the width of the narrow bags 32N. That is, the cutter is shifted toward the datum line between the cutter and the datum line becomes 1.5

inches. Finally, the seal bars 50 may be adjusted toward the cutter to reduce the spacing SC-N between the seal bars and the cutter to 9 inches which is a multiple of width of the narrow bags 32N.

Now, when the folded web 30 is advanced along the path, the sealing bars 50 will form the side seals 51 at 3 inch increments thereby to form the narrow bags 32N. Then, with each advance of the web, one bag 32N will advance past the cutter 55 and will dwell with its trailing seal positioned in line with the cutter. Since the spacing CD-N between the cutter and datum line is 1.5 inches or half the width of the bag 32N, the latter, like the wider bag 32, will dwell during cutoff with its vertical center line centered exactly on the datum line DL. Because the bag 32N is narrower, however, its leading edge will assume a different position in the transfer station 56 than did the leading edges of the previously formed bags 32, and will be disposed 0.5 of an inch closer to the datum line.

To effect transfer of the narrow bags 32N to the conveyor 57 in spite of the difference in the positioning of their leading edges in the transfer station 56, the phasing of the clamps 69 relative to the datum line DL is changed between the two runs by bodily shifting of the chain 70 in order to adjust the clamps closer to the datum line and into position to receive and grip the leading edges of the narrow bags. That is to say, the chain is shifted bodily when the machine is changed over so that each pair of clamps presented to the transfer station will dwell in a gripping position which is closer to the datum line than the position occupied by the clamps during the preceding run. The difference between the two positions is equal to one-half the difference in bag width and, in the case of changing from 4 inch bags to 3 inch bags, the clamps are adjusted toward the datum line such that the spacing DG-N becomes 1.5 inches or 0.5 of an inch less than the previous spacing DG.

With the machine thus changed over, each narrow bag 32N is gripped by a pair of dwelling clamps 69 during cutoff and is centered automatically on the datum line DL to which the working centers of the operating mechanism are referenced. Accordingly, advance of the bag 32N by the chain 70 through steps of the same length as before causes the bag to dwell in the various stations with its vertical center line also positioned in exact coincidence with the centers of the mechanisms even though the latter remain set in the same positions as during the previous run. Thus, there is no need between runs to adjust such mechanisms as the bag opener 59, the dispenser 61 and the pick-off device 65 along the path and into alinement with the centers of the narrow bags. This is particularly important with respect to the dispenser which is quite large and difficult to adjust. Elimination of the need of adjustment of the dispenser and the other operating mechanisms therefore results in a substantial saving in the amount of time and effort required to change over the machine and thus significantly increases the versatility of the machine.

Adjustments similar but reverse to those described above are made when the machine is changed over from running the narrow three inch bags 32N to running wider bags 32W (FIG. 4) which, for example, may be inches wide. The feed rolls 66 and 67 are adjusted to advance a 5 inch length of web upon each step, the cutter 55 is adjusted away from the datum line DL by 1 additional inch to increase the spacing CD-W to 2.5 inches, and the sealing bars 50 are adjusted away from the cutter to increase the spacing SC-W to 10 inches or a multiple of the new bag width. After the chain 70 has been shifted to move the clamps 69 away from the datum line by one additional inch and to increase the spacing DG-W to 2.5 inches, the machine is ready to run the 5 inch bags. As before, each bag 32W first is centered on the datum line during cutoff and then dwells in each of the stations with its vertical center line coinciding with the working centers of the operating mechanisms. Accordingly, changing over of the machine to run wider bags also may be accomplished without adjustment of the mechanisms along the bag path and may be effected as quickly and easily as the changeover to narrow bags.

In addition to running bags of different widths, the same machine often may be changed over to form and fill a series of bags of a different height or length than those formed and filled during a preceding run. Changing over of the machine to form and fill bags of different lengths is simplified significantly by maintaining the upper ends of all bags positioned on a common top datum line regardless of the length of the bags and by advancing the bags with their upper ends extending along the datum line during forming and filling. in addition, the various mechanisms which operate on the tops of the bags (such as the splitters 53 and 54, the dispenser 61, and the top sealing and cooling bars 63 and 64) are alined with and arranged along the top datum line so that, by moving the upper ends of bags of all lengths along the datum line, the machine may be switched over to run longer or shorter bags without need of raising and lowering the top operating mechanisms between each run.

In the present instance, the machine is capable of forming bags ranging in length from 2 inches to 8 inches and is loaded with a web 30 of different width whenever a changeover is made to form bags which vary in length from those formed during the preceding run. To maintain the upper ends of all bags within the range lying along a common datum line, the elevation of the folding plow 47 is raised each time the machine is loaded with a narrower web to make shorter bags and is lowered each time the machine is loaded with a wider web to make longer bags.

As shown most clearly in FIGS. 2 and 6, the folding plow 47 is simply a flat V-shaped plate disposed in a downwardly inclined position immediately downstream from the guide roller 46 with the underside of the plow engaging the web 30 after the latter passes over the roller. The plow terminates at its lower end in a point 73 and coacts with a pair of upright pressing bars 74 on opposite sides of the point to depress the center of the web progressively downwardly and to fold the opposite side portions of the web progressively upwardly while pressing the side portions toward each other thereby to form the strips 49 as the web passes beneath the plow and between the folding rollers. Both the plow 47 and the bars 74 are suspended from a horizontal platform 75 which is mounted for vertical adjustment so that the plow and the rollers may be raised and lowered in unison when it is desired to change over the machine to form bags of different lengths. The two guide rollers 43 and 46 are joumaled on the forward end of the platform and also are raised and-lowered when the platform is adjusted.

To support the platform 75 for vertical adjustment, a cylindrical post 76 is telescoped slidably into a tubular sleeve 77 fastened within a hole 78 in the top of abaselike cabinet 79 (FIGS. and 6) and projecting upwardly from the cabinet along the rear side edgeof the plow. An arm 80 fastened to and projecting forwardly from the upper end of the post overhangs the platform and is connected thereto by locking screws 81 (FIG. 7) which may be adjusted for purposes of locating the platform in a level position. Raising and lowering of the platform to any position between those shown in full and in phantom in FIG. 6 may be effected simply by turning an actuator in the form of a hand crank 83 (FIG. 5) to slide the post upwardly or downwardly in the sleeve 77. The crank is conveniently accessible from the front side of the cabinet and is operably connected to a lead screw 84 by bevel gearing 85 housed within the cabinet. The screw projects upwardly through the top of the cabinet into a vertical bore 86 formed in the post and is threaded into a nut 87 which is fastened rigidly within the bore. Thus, rotation of the crank results in turning of the screw to slide the post 76 upwardly or downwardly in the sleeve 77 and thereby raise or lower the plow 47 to different elevations. A spring-loaded key 89 (FIG. 8) fastened to the sleeve and slidably fitted into a keyway formed in they post prevents the latter from turning when the crank is rotated.

To demonstrate the ease with which the machine may be changed over to handle bags of different lengths, let it be assumed that the machine initially has been set up to form bags 32 having a length of'5 inches out of a web 30 having a width of approximately inches. As the web moves beneath and is doubled upwardly-by the plow 47, the fold 34 of the resulting strips 49 will be disposed level with the lower point 73 of the plow (see FIG. 3) and the upper edges of the strips will be drawn upwardly to and will extend along a horizontal line TL (FIGS. 3 and 6) which herein defines the top datum line. With the splitters 53 and 54, the dispenser 61, and the top sealing and cooling bars 63 and 64 properly set up relative to and positioned along the top datum line, the bags are formed, filled and-closed in normal fashion as the web is drawn beneath the plow and as the machine cycle proceeds. 5

Now, if it is desired to adjust the machine to form and fill shorter bags 328 (FIG, 3), a narrower web of material is loaded into the machine and the plow 47 is raised from its original position by an amount corresponding to the difference in height of the bags 32 and the shorter bags 328, this amount being approximately equal to half the difference between the width of the original web 30 and the width of the narrower web. Because of the raised plow, the level of the lower fold of the narrow web will change as the web is doubled, but the edges of theweb still will be drawn upwardly into precise alinement with the same top datum line TL. As a result, the shorter bags may be formed and filled without lowering the splitters 53 and 54, the dispenser 61, the top sealing and cooling bars 63 and 64, and certain other operating mechanisms as other- 'wise would be necessary if the plow were held at a constant level for bags of all lengths.

To make longer bags 32L (FIG. 3) from a web wider than the original web 30, the plow 47 is simply lowered from its previous position by an increment equal to the difference between the length of the long bags 32!. and the length of the bags which were formed during the preceding run. Such lowering of the plow causes folding of the upper edges of the wide web to the level of the top datum line TL as shown in FIG. 3 thereby doing away with the need for adjusting or raising the different top operating mechanisms to accommodate the longer bags. Accordingly, by maintaining a constant top datum line TL for the bags, the number of adjustments necessary to change over the machine to handle bags of different lengths is considerably reduced thus enabling changeover to be accomplished easily and rapidly. While the terms length and height have been used specifically in reference to the vertical dimension of the bags and the term width has been used in reference to the horizontal dimension, it should be understood that these terms may be used interchangeably and do not necessarily imply that one dimension is greater than the other.

In accordance with one aspect of the invention and contributing significantly to the ease with which the machine may be changed over to running bars of different sizes are novel mounting arrangements for the side sealing bars 50 and the cutter 55 to permit quick, convenient and precise adjustment of these elements along the path of the web simply by operating actuators connected to the elements. As shown most clearly in FIGS. 5 and 9, the side sealing bars are fastened to and disposed within a rectangular frame 90 which is fastened at its lower end to a sleeve-like carriage 91. The latter, in turn, is telescoped slidably over an elongated tube 93 extending parallel to the web, one end of the tube being fastened releasably to one end plate of the cabinet 79 and the other end of the tube being fastened releasably to one end plate of a similar cabinet 94 disposed beneath the cutter. Fastened to and extending along the tube is a toothed rack 95 which meshes with a pinion 96 (FIG. 9a) housed within the carriage and mounted to turn about a vertical axis. The pinion is geared to an operating crank 97 joumaled in and projecting outwardly from the forward side of the carriage and, in response to turning of the crank, the pinion rotates in driving engagement with the rack to slide the carriage along the tube.

With this arrangement, the seal bars 50 may be adjusted to any desired position along the path of the web 30 simply by turning the crank 97'of the rack and pinion actuator. Preferably, a pointer 99 (FIG. 5) is attached to one end of the carriage 91 and runs along a calibrated scale I00 extending along the tube 93 thereby to indicate the position of the seal bars along the path at any given time.

In this instance, each side sealing bar 50 is reciprocated into and out of sealing engagement with the web 30 of a self-contained actuator in the form of a pneumatic ram 101. As shown in FIG. 9, each ram comprises a cylinder 103 slidably receiving a plunger 104 which is connected at its free end to one of the sealing bars, the latter extending substantially perpendi'cular to the plunger. In response to the flow of pressurized air into and out of the cylinders, the plungers are reciprocated back and forth to shift the bars toward and away from each other and into and out of sealing engagement with the web. Air flows to the cylinders through conduits (not shown) from a pressure source 105 (FIG. housed within the cabinet 79 and is controlled by solenoid-actuated valves (not shown) which are operated in timed relation with the advance of the web to cause shifting of the seal bars toward the web each time the latter dwells. The air conduits extend from the cabinet 79 to the cabinet 94 through a rectangular duct 106 (FIG. 9) extending horizontally between the upper rear corners of the cabinets and interconnecting the two. The cabinets are further interconnected by forward and rear frame members 107 extending between the lower corners of the cabinets with a diagonally inclined shield 109 anchored to the .-forward frame member and the duct to from collecting beneath the machine.

Advantageously, the side sealing bars 50 are long enough to form the seals 51 on the longest bags which are formed by the machine and thus the machine may be changed over to run bags of a different length without raising or lowering the bars between runs. In many instances, however, it is desirable to locate the plungers 104 at the vertical centers of the seals so that the sealing pressure exerted by the rams 101 will be distributed uniformly over the length of the seals. For this purpose, the invention contemplates mounting the rams for vertical adjustment relative to both the frame 90 and the seal bars to enable centering of the plungers along the seals when the machine is changed over to run longer or shorter bags.

To mount the rams 101 for vertical adjustment relative to the frame 90, the latter is formed with elongated vertical slots 110 (FIG. 5) through which the plungers 104 project inwardly toward the seal bars 50. Each ram is secured to the outer side of the frame by a clamping plate 111 (FIG. 9) which may be bolted in various vertical positions on the frame to enable raising and lowering of the ram with the plunger moving within slot 110. An elongated connecting strip 113 is attached to the free or inner end of each ram and is formed with a vertically extending tongue which slidably interfits with a groove formed in a similar connecting strip 114 fastened to the outer side of each seal bar, the two opposing strips being releasably fastened together by screws 115. Centering of each plunger 104 on the vertical center of the seals 51 may be accomplished by loosening the screws 115 to release the plungers from the seal bars 51 and holding the latter at a desired level while the rams are released from the frame by loosening of the clamping plates 111. After the rams have been raised or lowered to center the plungers vertically with respect to the bags of the next run, the pairs of connecting strips 113 and 114 and the plates 111 are re-clamped to anchor the rams and the bars in the desired positions.

Like the sealing bars 50, the cutter 55 is sufficiently long to sever bags of maximum length from the web and does not require vertical adjustment when the machine is changed over to run longer or shorter bags. Herein, the cutter comprises a swingable blade- 116 (FIGS. 12 and 15) movable transversely of the folded web and across a fixed blade 117 with a scissors action prevent debris cabinet 94 through a hole 121 (FIG. 11) formed in a platform 123 which overlies and covers an opening 124 (FIG. 10) formed in the top of the cabinet 94. Near its lower end, the lever is pivoted for back and forth swi nging on a pin 125 (FIG. 12) rigid with and projecting axially from a circular disk 126 which is bolted releasably to one end wall of an underslung case 127 anchored to the lower side of the platform 123 and housed within the cabinet 94 in vertical alinement with the top opening 124.

To swing the movable blade 1 16 relative to the fixed blade 117, an air cylinder 129 (FIG. 12) is attached to the case 127 and includes a reciprocating plunger 130 pivotally connected to the lower end of the lever 120 and operable to rock the latter and the blade 116 about the pin 125 in response to the admission of pressurized air from the conduits in the duct 106 into alternate ends of the cylinder under the control of a solenoid actuated valve (not shown). Swinging of the movable blade 116 carries its cutting edge across the cutting edge of the stationary blade 117 to shear the web 30 along one of the seals 51, the latter blade being positioned to coact with the cutting edge of the swinging blade and being fixed to one edge of a plate 131 upstanding from the platform 123. The web is guided between the two blades and is pressed against the cutting edge of the fixed blade during cut off by a spring metal strip 133 (FIG. 15) extending lengthwise of the blades adjacent the cutting edges.

In response to swinging of the movable blade 116, a flying splitter 134 (FIGS. 11 to 13) is swung upwardly from a normal position disposed between the upper edges of the folded web 30 to a raised position disposed out of the way of the swinging blade. The flying splitter is located within a gap defined by adjacent ends of the splitter bars 53 and 54 and is suspended from a shaft 135 journaled to turn on a top plate 136 supported above the platform 123. As the web advances, the flying splitter holds the upper edges of the web spread apart as the latter passes between the blades 116 and 117 and through the gap between the splitters 53 and 54. During each dwell when the movable blade is swung through its cutting stroke, the splitter is rocked upwardly and out of the path of the blade by a crank 137 fastened to the lever 120 and connected by a link 139 to a crank 140 on the shaft 135.

In order to enable adjustment of the cutter 55 along the path when the machine is changed over to run wider or narrower bags, the platform 123 is mounted for back and forth sliding on the top of the cabinet 94, with the case 127 moving within the opening 124 during such sliding. As shown in FIGS. 12 and 14, rollers 141 joumaled on upright pins 143 depending from the platform are engageable with the side edges of the opening 124 to guide the platform and to keep the platform from shifting laterally on the cabinet 94. Quick and simple adjustment of the position of the platform and the cutter along the path may be accomplished by turning of an actuator in the form of a lead screw 144 which is threaded into a nut 145 detachably fastened to the forward side wall of the case 127. The screw extends through and is mounted rotatably in the end walls of the cabinet 94 and is adapted to be rotated by a hand crank (not shown) fastened to one end of the screw. A pointer 146 (FIG. 12) is carried on the platform near the forward side edge thereof and runs along a scale on the top of the cabinet to indicate the distance of the cutter from the datum line DL. Since the flying splitter 134 also is carried by the platform 123, it is adjusted along the path with the cutter and always remains in the same working position relative to the cutter.

The feed rolls 66 and 67 also are mounted onthe platform 123 for adjustment in unison with the cutter 55 so that a fixed horizontal spacing may be maintained between the rolls and the cutter in all adjusted positions of the latter. For this purpose, the rolls are journaled at their upper ends by the same top plate 136 carrying the splitter l34'and are journaled at their lower ends by the platform 123 so as to be movable with the platform. The rolls are spaced upstream from the cutter only far enough to establish sufficient clearance between the two to allow manual threading of the web 30 at the start of a run and, by adjusting the cutter and the rolls in unison, the clearance always remains fixed at a small value to utilize with maximum effectiveness the lateral support provided on the web by the rolls during severing of the bags from the web.

Intermittent rotative driven for the feed rolls 66 and 67 is produced by a power module housed within the cabinet 94 and includingan electric motor 147 (FIG.

11) connected by an endless belt 149 to a gear box 150 having an output shaft 151 which mounts a variable throw crank 153. The latter is coupled by a pitman 154 to a second crank 155 fast on an internally splined horizontal sleeve 156 whose one end is journaled in the front end wall of the cabinet. An externally splined shaft 157 journaledon the underside of the platform 123 is telescoped slidably into the sleeve 156 and is coupled by means of an electro-magnetic clutch 159 to gearing (not shown) housed within the casing 127 and rotatably coupled to the feed rolls 66 and 67. With this arrangement, the pitman 154 reciprocates up and down through one cycle in response to rotation of the output shaft 151 and the crank 153 through one revolution and acts through the crank 155 to oscillate the sleeve 156 and the shaft 157 back and forth about their axes. On the downstroke of the pitman, the direction of rotation of the shaft 157 corresponds to that necessary to rotate the feed rolls in a direction advancing the web 30 and, during the downstroke, the clutch 159 is energized to transmit the movement of the shaft 157 to the rolls to rotate the latter. Before the output shaft 151 completes one half revolution to start the pitman 154 through its upstroke, the clutch is de-energized to prevent the shaft'157 from driving the feed rolls reversely. The sliding fit between the splined sleeve 156 and the splined shaft 157 enables adjustment of the feed rolls along the path with the platform 123 while still maintaining a driving connection from the sleeve to the shaft and the feed rolls.

In setting up the machine, the throw of the crank 153 is adjusted to cause rotation of the feed rolls 66 and 67 through arcs somewhat greater than are necessary to advance the web 30 through steps equal in length to the width of the bags to be run. As the pitman 154 starts through its downstroke, the clutch 159 is energized to cause rotation of the feed rolls and advancement of the web. Each time the web moves through a step of desired length, a photo-electric scanner 160 supported alongside the path on the top plate 136 detects one of a series of targets 161 (FIG. 4) pre-printed on the web and spaced from each other in accordance with the width of the bags. In response to such detection, the scanner produces an electric signal to energize an electro-magnetic brake 163 (FIG. 11) which acts on the shaft 157 to arrest further rotation of the feed rolls and to stop movement of theweb precisely upon completion of a step of desired length. The clutch slips for a short time while the brake is energized and then both the clutch and the brake are de-energized simultaneously before the pitman 154 starts on its upstroke to tum the shaft 157 in the opposite direction. As the web dwells, a one-way clutch 164 connected to the feed rolls positively prevents any reverse rotation of the rolls tending to result from the force exerted by the tensioned web.

In addition to rotating the feed rolls 66 and 67, the electric motor 147 drives a rotatable cycle shaft 165 (FIG. 11) which is operable both to advance the chain 70 of the conveyor 57 and to actuate many of the operating mechanisms of the bag-filling section 39. As shown in FIG. 11, the cycle shaft is coupled to a second output shaft 166 of the gear box 150 and is driven -in timed relation with the output shaft 151 thus synchronizing the cycle shaft with the advance of the web. The cycle shaft is journaled in the righthand end wall of the cabinet 94 and projects downstream to the extreme right-hand end of the bag-filling section, the shaft extending parallel to the conveyor with its axis located along the longitudinal center line of the machine in vertical alinement with the path of the web and the bags. To advantage, the left-hand end of the cycle shaft is disposed beneath the feed rolls near the downstream end of the bag-making section 37 and need not extend further back upstream along the bagmaking section since the seal bars 50 are actuated by their own self-contained pneumatic rams 101 and do not require reciprocating mechanical linkages operated by the cycle shaft as has been customary with prior machines of the same general type. Thus, through the use of modular rams for operating the sealing bars, the left end of the cycle shaft may be located near the center of the machine at the downstream end of the bag-making section and the shaft may be substantially shorter than formerly required thereby reducing torsional deflection occurring in the shaft and resulting in more precise synchronism between the operating mechanisms.

Rotatable with the cycle shaft and housed within the cabinet 94 are two cams (FIG. 11) which sequentially open and close limit switches 169 at timed intervals as the cycle shaft rotates, one of the switches controlling energization and de-energization of the clutch controlling the valve for the cutter actuator 129 and for controlling the dispenser and various other mechanisms of the bag-filling section 39. The electrical wiring connecting the switches and the mechanisms is strung through the duct 106 and is connected into a control panel 174 (FIG. 5) which upstands from the top of the cabinet 79 along the rear side thereof.

Since the seal bars 50, the cutter 55 and the feed clutch 159 of the bag-making section 37 are all controlled electrically, the machine is quite flexible in operation and may be easily programmed with different switching sequences to form widely varying widths of bags of multi-pocket bags. By holding the clutch deenergized while continuing to drive the bag-filling section 39 with the cycle shaft 165, the web feed may be stopped to allow clearing of the bag-filling section of previously formed bags. In addition, the electrically controlled components of the bag-making section may be operated in response to demand signals from the dispenser 61 so as to continue or discontinue the forming of bags as dictated by conditions prevailing in the bag-filling section.

The right-hand end of the cycle shaft 165 is disposed near the downstream end'of the bag-filling section 39 and drives one input shaft 175 of an intermittent transmission 176 (FIG. 16) which, in turn, rapidly advances the chain 70 of the conveyor 57 through one step at the beginning of each revolution of the cycle shaft and then allows the chain to dwell during the remainder of the revolution. The transmission is supported on a baselike cabinet 177 and is covered by a peaked roof 179 (FIGS. 16 and 18) whose one end is telescoped into a complementary shape end cover 180 (FIG. 16) positioned on the base. From the end cover, the roof extends upstream over the entire length of the bag-filling section and is detachably fastened at its opposite end to one end wall of the center cabinet 94. As shown most clearly in FIG. 18, the roof is formed by a pair of downwardly inclined plates 181 joined together at their upper ends to define an inverted V with its peak 183 overlying the cycle shaft 165 and advantageously disposed in vertical alinement with the axis of the shaft and the path of the bags. The downwardly sloping side plates effectively cover the shaft and the transmission 176 and cause shedding to the floor of any loose product which is spilled during the filling operation. In this way, the roof prevents the underlying elements of the bag-filling section from becoming fouled by the product after continued service use of the machine. Moreover, the sloping plates of the roof may be dusted or washed down quite easily to simplify cleaning of the machine.

To advance the chain 70 of the conveyor 57, the transmission 176 includes an intermittently rotatable drive shaft 184 projecting upwardly through the roof 179 to the rear side of the peak 183 and mounting a sprocket I85 around which the chain is trained. The chain includes a pair of straight runs extending horizontally above the roof from the sprocket toward the transfer station 56 with the forward run of the chain being in substantial horizontal alinement with the path of the web and being in substantial vertical alinement with the axis of the cycle shaft. At its upstream end, the .chain is guided by two laterally ofiset idler sprockets 186 (FIGS. 11 and 18) joumaled to turn about vertical axes on a horizontal plate 187 which is received within the legs of a U-shaped yoke 189 disposed between the runs of the chain. Several yokes are spaced along the bag-filling section 39 and are fastened to similarly spaced bridges 190 (FIG. 18) each of which includes upright side walls 191 connected to the plates 181 of the roof and spanned at their upper ends by a horizontal top wall 193 extending across the peak 183 of the roof and serving to support one or more of the operating mechanisms.

Adjustment of the positions to which the clamps 69 are presented to the transfer station 56 for wider or narrower bags is accomplished simply by shifting the chain bodily relative to the drive shaft 184 of the transmission 176 in order that all of the clamps may be phased in unison without having to change the individual positions of the clamps on the chain when changing over to a different bag width. To these ends, the drive sprocket is adapted to be adjusted to various angular positions on the shaft 184 so that the chain may be shifted relative to the shaft to change the positions in which the clamps stop when the shaft and the chain dwell. As shown in FIGS. 16 and 17, the sprocket 185 overlies a hub 194 which is keyed for rotation with the shaft. The sprocket is anchored to the hub by angularly spaced bolts 195 extending downwardly through arcuate slots 196 in the sprocket and threaded into holes in the hub.

When changing over the machine to form narrower bags, the drive to the chain 70 is stopped just after the latterhas completed one step. The bolts 195 are loosened and the drive sprocket 185 is turned clockwise (FIG. 17) on the hub 194 and the shaft 184 through an angle sufficient to shift the forward run of the chain and each pair of clamps 69 thereon toward the datum line DL by an amount necessary to enable the clamps to pick up the narrow bags in the transfer station 56. Accordingly, with the sprocket re-clamped to the hub, the clamps will stop in their new positions each time the chain dwells during the subsequent run. The same procedure is followed when the machine is changed over to run wider bags except that the sprocket is turned counterclockwise on the hub to shift the clamps on the forward run of the chain away from the datum line DL.

In another of its aspects, the present invention contemplates mounting the chain 70 below the level of the bottoms of the longest bags which are run on the machine in order to place the chain out of the way of all of the operating mechanisms disposed along the path of the bags and thereby keep the chain from interfering with efiicient operation of the mechanisms. In addition, provision is made of a novel guide 197 (FIG. 18) which not only supports the chain as the latter advances through the filling station 60 but which also completely encloses the top and the sides of the chain to prevent any loose product from settling on and fouling the chain.

As shown in FIGS. 16 and 18, the drive sprocket 185 and the idler sprockets 186 are disposed well beneath the level of the lower clamps 69 and guide the chain 70 for movement in a horizontal plane which is spaced downwardly from the top datum line TL by approximately fourteen inches. With the chain thus running below the bottoms of the longest bags, the operating 17 mechanisms may work freely on thebags without having their range of movement restricted by the chain and Without being specifically designed to avoid interference with the chain.

To protect the chain'70 from loose product while preventing the chain from sagging downwardly as it runs between the sprockets .185 and 186, the guide 197 extends horizontally along the entire forward run of the chain and comprises two side members 199 releasably bolted together and defining a downwardly opening, inverted U-shaped channel 200 within which the chain is guided. Near their lower ends, the side members are formed with inturned flanges 201 projecting inwardly toward the sides of the chain and defining a track upon which the'upper connecting links of the chain ride to prevent downward sagging of the chain. The top and the spaced apart sides of theguide enclose ,the top and the sides, respectively, of the chain and thus loose product can neither settle on the chain nor accumulate in the channel vto-interfere with smooth running of the chain. Moreover, the chain may be effectively lubricated within the channel without danger of powdered or granular product sticking to the lubricant and fouling the chain. Along its rear run, the chain is supported and protected by a guide 197' identical in construction to the guide 197 but extending along a somewhat shorter length of the chain in the area of the filling station 60. 5

For supporting the clamps 69 for movement with the chain 70, carrier bars 203 (FIG. 18) are spaced along the chain in accordance with the pitch of the clamps and each includes an upright body portion 204 which vprojects upwardly above the chain in substantial vertical alinement therewith and which is sufficiently long to-support a pair of vertically spaced clamps with the lower clamp. disposed at a higher elevation than the chain even when bags of maximum length are being run. Each carrier bar is formed at its lower endwith a generally C-shaped connector 205 bent outwardly, downwardly and then inwardly around the chain guide 197 and terminating in a horizontal arm 206 underlying the guide and fastened to the exposed underside of the chain by an elongated pin 207 which also serves to connect adjacent links of the chain. The upper end portion of each long pin 207 projects above the upper side of the chain and journals an anti-friction roller 209 which rides in the channel 200 in rolling engagement with the inner sides of the side members 199 to restrict sidewise I jaw 213 and fastened to the inner face of the jaw. The

other arm 216 of the clip extends alongside the outer face of the fixed jaw and cooperates at its trailing free end with the corresponding end of the jaw to form a clamp for gripping the bags. By virtue of its resiliency, the outer arm 216 is urged to a closed position against the fixed jaw to hold the bags and is adapted to be spread to an open position to receive and release the bags. For this purpose, each clamp 69 includes an operating lever 217 formed with a pair of legs 219 projecting beyond and straddling the bight portion of the spring metal clip and substantially centered with respect to the long axis of the clip. The two legs are formed integrally with and are interconnected at their trailing ends by a flat plate 220 spanning the legs and mounted toswing about a fulcrum formed by a substantially spherical ball 221 fastened to the outer face of the fixed jaw 213 intermediate the ends of the arm 216. To open the clamp, the legs 219 of the lever are forced inwardly toward the carrier bar 203 to rock the trailing end of the plate 220 outwardly about the fulcrum 221 and thereby move the free end of the arm 216 outwardly away from the fixed jaw 213. When the legs are released, the resilient arm 216 automatically returns to its closed positionand rocks the lever in the opposite movement of the chain and to prevent the chain from 1 twisting under the weight of the clamps 69 and the car-. rier bars 203. With the body portions 204 of the carrier bars alined vertically with the chain, the tendency of the latter to twist is reduced since the center of gravity of each bar and its attached clamps is offset outwardly from the chain by only a very slight distance.

According to another feature of the invention, the clamps 69 are formed as self-contained cartridges usable universally with bags of different sizes with each of the cartridges being identical in size and construction to facilitate their manufacture by mass production techniques with a minimum amount of tooling. Herein, each clamp includes a supporting block 210 (FIG. 19) which is fastened to the outer side of one of the carrier bars 203 by a screw 211 (FIG. 18) extending through the upright body 204 of the bar and threaded into the direction.

Since the upper ends of both long and short bags extend along the same top datum line TL, the upper clamp 69 of each pair may be mounted near the upper end of its respective carrier bar 203 and need not be raised or lowered between runs of bags of different lengths. Moreover, the upper ends of the carrier bars are constantly positioned at a level sufficiently low to be out of the way of the operating mechanisms, (such as the top sealing bars 63) so that shorter carrier bars need not be installed on the chain 70 when the machine is changed over to run shorter bags. If the length of the bags is significantly changed, the lower clamps may be raised or lowered to accommodate the shorter or longer bags simply by fastening each lower clamp at a different level on its respective bar with the attaching screw 21] extending through a different one of a series of vertically spaced holes 223 (FIG. 18) formed in the bar.

Thus, by maintaining the top datum line TL constant, only one size of carrier bars 203 and one size of clamps 69 are necessary to handle bags of different lengths. Instead of installing a different set of carrier bars and clamps between runs, it is necessary only to make a simple adjustment in the position of the lower clamps. The clamps therefore are manufactured as self-contained cartridges separate from the carrier bar and, since the clamps are each identical in construction, only a single tooling set up is required to produce cartridges capable of handling bags of all sizes.

In order to open and close the clamps 69, a clamp operator 224 (FIGS. 16 and 18) is positioned in the transfer station 56 alongside the chain 70 and acts to open and close the two clamps in the transfer station simultaneously during each dwell of the chain. A similar clamp operator 225 (FIG. 16) is located just downstream from the pick-off device 65 and opens the clamps again just before the filled bags are removed from the clamps by the pick-E device.

As shown in FIG. 18, each clamp operator 224, 225 includes a vertical .operating roller 226 which oscillates back and forth about an upright axis and into and out of engagement with the legs 219 of both clamps 69 in the transfer station 56 to rock the levers 217 about their fulcrums 221. As the roller swings into engagement with each lever, it rolls along the legs with relatively friction-free motion while rocking the legs toward the carrier bar 203 to open the clamp. The clamp returns to its closed position as the roller swings away from the lever to allow the resilient arm 216 to flex inwardly. Each roller is rotatably carried by an upright bar 227 which is fastened to the free end of a horizontal arm 229 connected to and projecting upstream from a mounting head 230. The rollers are sufficiently long to engage the levers of the upper and lower clamps regardless of the positioning of the lower clamps on the carrier bars and thus it is not necessary to adjust the rollers vertically when changing over the machine to run bags of different lengths. When the phasing of the clamps is changed to accommodate longer or shorter bags, it is desirable to adjust the rollers along the path into positions corresponding to the new dwell positions of the clamps in order to insure proper engagement of the rollers with the levers 217. To enable such adjustment, each horizontal supporting arm 229 is formed with an elongated slot 231 (FIG. 16) and is fastened to its respective mounting head 230 by a screw 233 (FIG. 18) extending through the slot.

The mounting head 230 for each roller 226 is fast on the upper end of an elongated sleeve 234 which is journaled for rotation within an outer supporting sleeve 235 anchored to one of the bridges 190 and projecting downwardly through the roof 179. The lower end of the inner sleeve 234 extends downwardly beyond the lower end of the outer sleeve and carries a follower 236 positioned to ride against a rotatable cam 237 on the cycle shaft 165. Each time a rise on the cam rotates past the follower, the inner sleeve is rotated within the outer sleeve to swing the roller 226 away from the clamps 69 and allow the latter to close.

To swing the roller 226 toward the clamps 69, an elongated torsion bar 239 made of resilient metal is telescoped into the inner sleeve 234 with its upper end keyed to the sleeve as indicated at 240 and with its lower end anchored to a frame member 241 on the inner side of the roof 179. In response to outward swinging of the roller, the torsion bar winds up or becomes twisted intermediate its ends as the inner sleeve 234 is turned by the rise on the cam 237. When the follower 236 encounters a fall on the cam, the torsion bar relaxes and unwinds to turn the sleeve 234 in the opposite direction and to swing the roller inwardly to open the clamps. In addition to providing a comparatively simple arrangement for swinging the roller through its opening stroke, the torsion bar 239 is relatively trouble-free and has a long service life since torsional stresses are distributed over its length and build up at a slow rate.

Preferably, the lower end of the torsion bar 239 is fitted loosely within a hole in the frame member 241 and is anchored to the frame member by a crank arm 243 (FIGS. 18 and 20) which may be adjusted angularly to preload the torsion bar and thus enable adjustment in the amount of pressure exerted by the roller 226 on the clamps 69. A screw 244 extending upwardly through an arcuate slot 245 in the frame member is threaded into the free end of the crank arm and may be loosened to permit clockwise turning of the crank and twisting of the lower end of the torsion bar relative to the inner sleeve 234 while the latter is held stationary by engagement of the follower 236 with the cam 237. After the crank has been turned sufficiently to preload the torsion bar with the desired amount of force, the screw is tightened to anchor the crank and the bar to the frame. An adjusting screw 246 is threaded into the frame member and abuts against the anchoring screw 244 to facilitate turning of the crank. I

After the bags have been opened and filled in the filling station 60, they are advanced first between the top sealing bars 63 and then between the top cooling bars 64 (FIG. 16). The top sealing and cooling bars are reciprocated into and out of engagement with the tops of the bags by pneumatic rams 273 and 274, respectively, which are similar to the rams 101 used for reciprocating the side sealing bars 50. As explained above, the top sealing and cooling bars need not be raised or lowered to accommodate longer or shorter bags since the upper ends of all bags are held at a constant level on the top datum line TL. In addition, both wide and narrow bags are centered relative to the plungers of the rams 273, 274 and thus it is not necessary to adjust the rams along the path to keep the sealing pressure centered lengthwise of the top seals 36.

Upon being sealed and cooled, the bags 32 are advanced downstream to the pick-off device 65 which removes the bags from the clamps 69, swings the bags laterally and downwardly through a right angle, and deposits the bags in horizontal positions on a conveyor (not shown) for carrying the bags to the cartoner. Reference may be made to the above-mentioned application for a detailed description of the pick-off device and also for certain other mechanisms and features of the machine.

We claim as our invention:

1. In a packaging machine having a frame, mechanism on said frame for supporting and advancing face-to-face strips of flexible material along a predetermined path, an elongated heated sealing bar disposed on one side of said path and extending crosswise of said strips, a fluid-actuated operator, said operator comprising a cylinder having a reciprocating plunger extending substantially perpendicular to said sealing bar and operable in response to the flow of pressure fluid into and out of the cylinder to move the bar toward and away from the strips in timed relation with the advance of the strips whereby the bar momentarily engages the strips and forms longitudinally spaced seals extending crosswise of the strips, the improvement in said machine comprising, means connecting the free end of said plunger to said bar for selective adjustment of the 

1. In a packaging machine having a frame, mechanism on said frame for supporting and advancing face-to-face strips of flexible material along a predetermined path, an elongated heated sealing bar disposed on one side of said path and extending crosswise of said strips, a fluid-actuated operator, said operator comprising a cylinder having a reciprocating plunger extending substantially perpendicular to said sealing bar and operable in response to the flow of pressure fluid into and out of the cylinder to move the bar toward and away from the strips in timed relation with the advance of the strips whereby the bar momentarily engages the strips and forms longitudinally spaced seals extending crosswise of the strips, the improvement in said machine comprising, means connecting the free end of said plunger to said bar for selective adjustment of the plunger in a direction longitudinally of the bar, and means connecting said cylinder to said frame for selective adjustment of the cylinder relative to the frame in a corresponding direction whereby said plunger may be adjustably positioned in alinement with the lengthwise center of each seal regardless of the length of the seal.
 2. A packaging machine for handling bags which may vary in length within a predetermined range of lengths, said machine comprising a frame, a conveyor mounted on said frame for advancement along a predetermined path, a series of upright carrier bars fastened to and spaced along said conveyor, at least one bag holding clamp on each of said carrier bars and movable between open and closed positions, a clamp operating mechanism positioned alongside said conveyor and having an operator movable in opposite directions into and out of engagement with said clamps to open and close the latter, a sleeve rotatably mounted on said frame with said operator being fastened to and carried by one side of said sleeve, an actuator operable at spaced intervals to rotate said sleeve in one direction and thereby swing said operator in one direction relative to said clamps, and a resiliently flexible torsion bar telescoped into said sleeve with its one end anchored to the sleeve and with its other end anchored to said frame, said torsion bar being wound in response to rotation of said sleeve in said one direction and then unwinding when said actuator is idle thereby to rotate said sleeve in the opposite direction.
 3. A packaging machine as defined in claim 2 in which the other end of said torsion bar is rotatable relative to said frame, and means fast on the other end of said torsion bar and adapted to be anchored in various angular positions on said frame to enable preloading of the torsion bar with a selected amount of torsional stress.
 4. A packaging machine as defined in claim 2 in which two clamps are fastened to each of said carrier bars in vertically spaced relation to hold the upper and lower end portions of a bag, at least one of said clamps being adjustable toward and away from the other clamp to accommodate bags of different length within said range, said operator comprising an upright member sufficiently long to engage each clamp of the pair when the clamps are adjusted to accommodate the longest bag within said range.
 5. In a packaging machine having a dispenser for depositing a charge of product into a series of bags advanced successively beneath the dispenser, the combination of, a frame having sprockets journaled thereon, a bag conveyor comprising an endless chain trained around said sprockets and having at least one straight run adapted to travel in a horizontal path below the dispenser, a combined enclosure and guide support for said chain and comprising an inverted U-shaped member fastEned to said frame and extending along a substantial length of said straight run, said U-shaped member being formed with a top and with spaced apart depending sides protectively enclosing the top and the sides, respectively, of the chain from the product and defining a downwardly opening channel sized and shaped to receive and guide the chain as the latter travels along said path, the lower ends of the sides of said U-shaped member being formed with inturned flanges projecting inwardly toward the sides of the chain and defining a track preventing sagging of the chain, a series of carrier bars spaced along and projecting upwardly from said chain and fastened to the underside thereof, a series of rollers attached to the top of said chain with one roller above each carrier bar and riding in said channel along the sides of said U-shaped member to prevent twisting and sidewise movement of said chain, and at least one gripper attached to each of said carrier bars and adapted to support a bag for advancement with said chain.
 6. A machine as defined in claim 5 in which each of said carrier bars comprises a horizontal arm fastened at one end to the underside of the chain and projecting outwardly from the latter, and an upright body fastened to and projecting from the other end of said horizontal arm and supporting a gripper above the level of the chain.
 7. A clamping unit comprising an upright carrier bar; a pair of cartridges detachably fastened to said bar in vertically spaced relation with at least one of said cartridges being mounted for selective vertical adjustment toward and away from the other cartridge; said cartridges being identical in construction and each comprising a block, a U-shaped member of resilient material having a bight portion and having elongated arms straddling said block with one of the arms extending alongside one face of the block, the free end portion of the second arm extending alongside and cooperating with the other face of the block to form a clamp, a fulcrum located between said second arm and the other face of said block and supported by the latter; and separate actuating levers for each of said cartridges; each lever being swingable about the fulcrum of its respective cartridge and having one end portion projecting in one direction from said fulcrum toward the free end of said second arm and engageable with the second arm to move the latter away from said block in response to rocking of the lever about the fulcrum, and each lever having an opposite end portion projecting in the opposite direction from its respective fulcrum and extending beyond the bight portion of its respective cartridge. 